First I believe if you look at the panel in front of the chassis batteries there are two posts and a sign that says "connect here to jump start" connect there to charge.
Second the Trickle Charger that Tiffin puts on coaches will draw down the chassis battery if there is no shore power! unplugging it won't help. There is'should be fuse near the batteries (relatively low amp 10 or 15) that powers the board in the Trickle Charger, pull that fuse when storing without shore power. You know it is the right one when the green light stops blinking. Hope this all helps some.